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LAX92LA006 · Bentley MONGOOSE A

5 Oct 1991 · Boulder City, NV, United States

Bentley MONGOOSE A · Accident: on ground/water collision with terrain/water during takeoff

From an unrecorded airport to No airport

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Event

NTSB case
LAX92LA006
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
2 · all aircraft and ground
Ground fatalities
0
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Bentley MONGOOSE A

Aircraft type
Bentley MONGOOSE
Category
Gyroplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N7143K
Operator
Bentley, Richard F · private individual
Onboard fatalities
Unknown
Route
From not recordedTo No airport
Aircraft age
Not recorded
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Takeoff · roll/run
First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
On ground/water collision with terrain/water
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Destroyed

Cause areas

  • Pilot in command › Preflight planning/preparation, poor
  • Pilot in command › Unsuitable terrain or takeoff/landing/taxi area, selected

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

THE PLT'S MED CERT WAS EXPIRED & HE DID NOT HOLD A ROTORCRAFT CATEGORY RATING. DRG AN EXAM OF THE WRECKAGE, STRONG ROTATIONAL SIGNATURES WERE EVIDENT ON BOTH THE PROP & MAIN ROTOR BLADES. NO ACFT SYS ABNORMALITIES WERE FND DRG THE EXAM OF THE WRECKAGE. WHEEL TRACKS & IMPACT GND SCARS WERE FND ON THE DRY LAKE BED SURFACE. THREE TIRE TRACKS MATCHING THE DIMENSIONAL GEOMETRY OF THE LNDG GEAR WERE FND EXTENDING FOR A DISTANCE OF ABOUT 150 YDS. AN ADDITIONAL 15 YDS OF MAIN GEAR ONLY TRACKS WERE FND, WHICH TERMINATED AT A BERM. HVY GOUGE MARKS WERE NOTED ON THE TOP OF THE BERM, WHICH MATCHED ALL 3 LNDG GEAR. ABOUT 105 YDS BEYOND THE BERM, A GND IMPACT CRATER WAS OBSERVED, FOLLOWED BY A DISTURBANCE IN THE DIRT WHICH CULMINATED IN THE GYROCOPTER WRECKAGE. THE GYROCOPTER HAD NOT BEEN ISSUED AN AIRWORTHINESS CERTIFICATE IN ANY CATEGORY.

Probable cause

THE PILOT'S SELECTION OF AN INADEQUATE TAKEOFF AREA WHICH WAS TOO SHORT FOR THE PREVAILING CONDITIONS.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX92LA006
Event ID
20001212X18316
Case number
LAX92LA006
Dataset
historical-pre2008
Source SHA-256
89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: b213bface448de31dc92982eff29d2ac7f6048bfae703e83b962ae81c1edcb4e; retrieved 2026-09-21T01:31:54.237Z.